Hi Burr, Hi Anis - the nice thing about using Offset for creating your doubled lines is that it is more general and can be used with any kind of curve that you have drawn, not just single line segments.

Here is another example where the base curve contains a freeform curve segment and an arc:



To create a double-line out of this, select the pieces (they just need to touch, you don't have to join them first Offset will join them automatically for you), then run Construct / Offset.

There are 2 modes for Offset - "Through point" where you pick a point and the offset is calculated at a distance that passes through that point, or "by distance" where you specify a particular distance and then pick which side of the original curve to offset to.

For doing different pieces you'll probably want to use the "by distance" method so it is easy to have a consistent distance when working on different parts separately. You can either switch the mode for this manually, or just type in a distance value which will switch the mode automatically as well.

So for instance in this case after running the Offset command, I typed in 3 <enter> to set the offset distance to 3, then clicked once on the inside of the shape, to produce this double-line result with just one shot of the Offset command:



It's the primary tool to use if you want to get double-lined type results.


It is possible to go to a 3D solid shape before this and use Shell like you were talking about earlier Burr, but it can often be a pretty good idea to do as much work in 2D as you can first before punching things out to 3D. There are just less pieces involved while you are working in 2D and that generally makes it easier to trim things, etc...

- Michael